1. Field of the Invention
The present invention relates to a face mask, particularly, but not exclusively, to an aircrew oxygen mask, and a facepiece therefor.
2. Description of the Prior Art
In a well-known aircrew oxygen mask, valves are mounted within a complex face-seal molding, and the whole mask must be stripped down to carry out valve replacement. The problem of frequent face-seal replacement has been somewhat alleviated by the use of silicone rubber in place of natural rubber, but the complexity of the face-seal moulding still makes the continued use of this kind of mask extremely expensive. Furthermore, the very complex molds producing the face-seal molding are extremely expensive to replace.
An object of the present invention is to provide a facepiece which is easier and less expensive to produce than known face-seal moldings, and to provide a face mask incorporating such a facepiece in which valve replacement is comparatively simple.